Switch and bus insulator stack



Jan. 25, 1938. R. L. M COY SWITCH AND BUS INSULATOR STACK Filed Nov. 6,1935 2 Sheets-Sheet l 35 6 790%? .43. fifg Jan. 25, 1938. R. L. MccoYSWITCH AND BUS INSULATOR STACK Filed Nov. 6, 1935 2 Sheets-Sheet 2Patented Jan. 25, 1938 PATENT OFFICE 5106.618 swrrca AND nus msum'roas'racx W L. New, Baltimore. 1111.,

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Locke Insulator Corporation, a corporation of Maryland Application am 0.ms, semiv No. 48,580"

6 m (Cl. 1318-418) The invention relates to an insulator assemblyadapted for supporting a disconnecting switch mechanism, a bus or thelike and has for its general object the provision of a novel insulatingand supporting structure embodying the combination of certain insulatorsimder compression and certain others under tension, which may be mountedeither in a vertical or a horizontal position and which is peculiarlyand adequately braced against cantilever strains or in fact anydistortion even under the most severe conditions of use.

It is well known that at the higher voltages, 220 kilovolts andupwardly, tall insulator stacks are required for supporting a switchmechanism, a bus, or other device. It has been found difllcult to builda completely self-supporting single post rigid enough to withstand thestresses involved without considerable deflection which causesdiillculty for instance in satisfactorily maintaining proper alinementof disconnecting switch contacts. Due to the inherent flexibility ofsingle post stacks, they present a considerable hazard under earthquakeconditions which frequently ocour in the western and intermountainterritory of this country. The flexibility of such stacks permits theinsulators to get into a periodic vibratory condition if earth tremorscontinue for any appreciable periodof time and may result in thedestruction of buses and switches.

It has been proposed to make use of tripod insulator stacks but thesehave proven diilicult to handle for several reasons. In disconnectingswitches it is generally desired that one of the stacks of the tripod becapable of rotation for the transmission of mechanical energy for theoperation of the switch contacts. Furthermore it is difficult to buildthe end fittings suiliciently accurately that when the stacks are boltedup they will fit together so neatly that no initial strains are set upin the stacks. Even where these precautions have been taken the tripodscheme is not particularly strong in torsion. Moreover when use is madeof a tripod arrangement involving three stacks of pedestal or similarinsulators, which are relatively expensive compared with other types,the cost becomes excessive.

It is with the above facts in view that I have devised the presentinvention which has for an important object the provision of a structureincluding a single stack of pedestal or other more or less similarinsulators adapted to be placed and maintained under compression andbraced by sets of other insulators under tension, the stack beingrotatable in case the structure is used for supporting a disconnectingswitch but being staprovide a structure of this character in which theinsulator unit under compression is mounted at its lower end for limitedrocking movement and in which the insulators under tension employed forbracing purposes are likewise pivotally connected, through theinterposition of suitable flttings, with the top of the insulator undercompression and to the main support upon which the entire structure ismounted, these features insuring that the tension in the sets of bracinginsulators will equalize and throw no initial cantilever strains on theunit under compression, the latter being at all times held rigidly sothat deflection will not occur even under the most adverse conditions,such for instance as in the event of earth tremors.

A further object of the invention is to provide an insulator assembly ofthis character equipped with means at the top and bottom for adequateprotection against flash-over, this feature requiring but simplefittings which may be readily applied.

An additional object is to provide a structure of this characterwhich onaccount of being constructed of standard insulators which are in regularquantity production will be simple and inexpensive to construct as wellas possessing the above mentioned advantageous characteristics whichrender it a distinct improvement in the art.

To the attainment of the foregoing and other objects and advantages, theinvention preferably consists in the details of construction and thearrangement and combination of parts to be hereinafter more fullydescribed and claimed, and illustrated in the accompanying drawings inwhich:

Figure l is a side elevation of a switch supporting insulator assemblyconstructed in accordance with the invention and illustrating it asmounted in a vertical position,

Figure 2 is a plan view of the top yoke,

Figure 3 is a cross section on the line 3-3 01' Figure 2,

Figure 4 is a detail vertical section through the bottom support orbearing for the compression receiving unit,

Figure 5 is a fragmentary elevation showing more clearly the mounting ofthe lower end of one of the sets of bracing insulators under ten- Figure6 is a side elevation of the structure showing it mounted in ahorizontal position.

Referring more particularly to the drawings 55 the numeral 10 designatesthe supporting base which may be of structural steel or otherconstruction and upon which the entire device is mounted. Suitablysecured upon this base is a support ll having its top formed with asocket l2 and also formed with a central opening l3. Rockably mountedupon the support I I is a bearing member H having a depending portionengaged within the socket l2. This bearing member H has a centralopening l6 through which and through the opening l3 extends a shaft I!provided at its upper end with a disk or adapter l8 suitably secured tothe bottom of the lowermost one of a series of superposed insulators l9here shown, for purposes of illustration, as of the pedestal type thoughcertain others could be employed. Interposed between the bearing 14 andthe adapter I8 is a thrust bearing here represented as of the ball typethough there is no particular limitation in this respect. Secured to thetop of the uppermost insulator I9 is an adapter 2| on the lower end of ashaft 22 adapted for connection with any ordinary or preferred type ofswitch contacts, not shown as being well known in the art. The shaft 22passes through a hole 23 in the hub portion 24 of a spider-liketriangular yoke 25 which has radial arms 26 formed at their ends withholes 21. Interposed between the adapter 2| and the hub portion 24 ofthe yoke is a thrust bearing 28.

For bracing the stack of pedestal insulators 19, I provide a pluralityof sets of insulators under tension arranged about the stack and hereshown, simply for purposes of illustration, as strings of suspensioninsulators 29 of any ordinary or preferred type but which are heredisclosed as of the variety equipped with ball and socket means forconnecting them in series. At the upper end of each string thereisprovided a fitting 3D and these fittings are pivotally connected at 3!with the ends of the arms of the triangular yoke, the holes 21 receivingthe necessary pivot bolts. At the lower end of each string is a fittingor bracket 32 and these are pivotally connected at 33 with eye bolts 34extending through the base l0. These eye bolts are equipped with nuts 35and interposed between the nuts and the base H) are coil springs 36which provide means whereby the strings of suspension insulators can beplaced under the desired predetermined tension so that the pedestalstack will be maintained rigid.

For protecting the entire structure against flash-over, I provide agrading ring 31 carried by a plurality of curved arms 38 suitablysecured to the arms 26 of the triangular yoke at the top of the pedestalstack. This ring 31 cooperates with a plurality of substantially halfrings 35 which are secured to the fittings or brackets 32 at the lowerends of the strings and which proiect outwardly away from the same andin an upwardly curved direction.

The entire assembly may be mounted in a vertical position as showninFigure 1 in which event it is preferable that all of the suspensioninsulators be arranged with their convex sides up. However, if it is sodesired, the assembly may be mounted upon a suitable support so as toextend horizontally in which event the uppermost string of suspensioninsulators would probably be reversed as shown in Figure 6. Thestructure is primarily intended as the support for a switch embodyingappropriate contacts adapted to be operated by the shaft 22 when theshaft H is rotated by any suitable means, not shown. Upon removal of thethrust bearings 20 and 28 the device is well adapted for use forsupporting a bus.

Reverting to the springs 36, it will be seen that it is a simple matterto determine definitely the amount of tension initially put on thesuspension insulator strings as these springs can be so designed andcalibrated that the coils will close tightly together at an accuratelydeter? mined value. Thus, in assembling, the constructor can draw thenuts 35 on the eye bolts 34 down until the coils of the springs areclosed and this will indicate definitely the amount of force which hasbeen applied. As the stack of pedestal insulators is rockably mounted atits lower end it can accommodate itself to the tension on the respectivestringsso that the forces will be equalized. All cantilever stress isremoved from the pedestal insulator stack which therefore operates onlyin direct compression. A distinct advantage of the entire assembly isthat it consists of standard types of insulators which are producedregularly in quantities and there is consequently no necessity for theconstruction of any special units.

From the foregoing description and a study of the drawings it will beapparent that I have thus provided an assembly which is highly efficientfor the purpose intended and which will be not only easy to assemble butalso inexpensive. It is thought from the above that the construction,operation and advantages will be readily apparent to one skilled in theart without further explanation.

While I have shown and described the preferred embodiment of theinvention, it should be understood that the disclosure is merely anexemplification of the principles' involved as the right is reserved tomake all such changes in the details of construction as will widen thefield of utility and increase the adaptability of the device providedsuch changes constitute no departure from the spirit of the invention orthe scope of the claims hereunto appended.

Having thus described the invention, I claim:

1. An insulator assembly comprising a base, a socketed bearing membermounted on said base, a stack of pedestal insulators rockably mounted onsaid bearing member, shafts connected, respectively, with the top andbottom of the stack, said shafts being designed and adapted for theoperation of switch means, a yoke at the upper end of the stack andthrough which the upper shaft extends, said yoke having a plurality ofarms, a plurality of strings of suspension insulators arranged in acircumferential series about the stack, fittings at the upper ends ofsaid strings pivotally connected with the yoke arms, eye bolts extendingthrough the base, and fittings at the lower ends of the stringspivotally connected with said eye bolts.

2. An insulator assembly comprising a. base, a socketed bearing membermounted on said base, a stack of pedestal insulators rockably mounted onsaid bearing member, shafts connected, respectively, with the top andbottom of the stack, said shafts being designed and adapted for theoperation of switch means, a yoke at the upper end of the stack andthrough which the upper shaft extends, said yoke having a plurality ofarms, a plurality of strings of suspension insulators arranged in acircumferential series about the stack, fittings at the upper ends ofsaid strings pivotally connected with the yoke arms, eye bolts extendingthrough the base, fittings at the lower ends of the strings pivotallyconnected with said eye bolts, and spring means associated with said eyebolts for applying a predetermined tension upon said strings.

3. An insulator assembly comprising a base, a socket member mounted onsaid base, a bearing member rocka'bly mounted on said socket mentber, astack of pedestal insulators, a thrust bearing interposed between saidbearing member andthe adjacent end of the stack, a shaft rotatablethrough said socket and bearing member. and connected with the end orthe stack, a second shaft secured to the other end of the stack, a yokethrough which said second named shaft extends, a thrust bearinginterposed between said yoke and the second named end of the stmk, aplurality of strings of suspension insulators ar ranged incircumferential series about the stack and pivotally connected with theyoke and with the base, and means for applying predetermined initialtension upon the strings.

4. An insulator assembly comprising a base, a socketed bearing membermounted on the base, an insulator rockably mounted on said heatingmember, shafts connected respectively with the top and bottom of theinsulator, said shafts being designed and. adapted for the operation ofswitch means, a yoke at the upper end of the insulator and through whichthe upper shaft ex tends, said yoke having a plurality of arms, aplurality of insulator members arranged in a cir cumferentiaiseriesabout the insulator, fittings at the upper ends oi said insulatormembers piv otally connected with the yoke arms and fittings at thelower ends of said insulator members pivotally connected to said base,said insulator mombers extending at acute angle to the insulator andserving to hold it under compression and from sldewise movement on itssupport.

5. An insulator assembly comprising a base, a socketed member mounted onthe base. an insulator rockably mounted on said bearing member, shafts(onnccted with the top and bottom of said insulator, said shafts beingdesigned and adapted for the operation of switch means, a yoke at theupper end of the insulator and through which the upper shaft extends,said yoke having a plurality of arms, a plurality of insulator membersarranged in a circumferential series about said insulator, fittings atthe upper ends of said insulator members pivotally connected with theyoke arms, spring means for connecting the lower ends of said insulatormembers to the base for applying a predetermined tension on saidinsulater members, said insulator members errtending at an acute angleto said insulator whereby they serve to hold said insulator undercompression and from sidewise movement on its support" 6. An insulatorassembly comprising a base, a rocketed bearing member mounted on thehere, an insulator rockably mounted on. said bearing member, a yokecarried by the upper insulator having a plurality of circumierentispaced radially extending arms, a pinrahty ct rsulator members arrangedin a oircumferen M series about the insulator, fittings at the un t endsof said insulator members pivotaliy n nected with the yoke arms andfittings at lower ends of said insulator members pivoteiiy connected tosaid base, said insulator members extending at an acute angle to theinsulator and having their points of connection to the base far therfrom the axis of the insulator than the points of connection to thearms, whereby they serve to hold said insulator under compression and.from sidewise movement on its support ROBERT L a

